Frequencies for first 10,000 rows of comstat4 variable in namcs2010 dataset :

composition status |
              code |      Freq.     Percent        Cum.
-------------------+-----------------------------------
single entity drug |      2,533       25.33       25.33
  combination drug |        303        3.03       28.36
      undetermined |         27        0.27       28.63
                 . |      7,137       71.37      100.00
-------------------+-----------------------------------
             Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016